/*
** $Id: lstate.h,v 2.24.1.2 2008/01/03 15:20:39 roberto Exp $
** Global State
** See Copyright Notice in lua.h
*/

#ifndef lstate_h
#define lstate_h

#include "lua.h"

#include "lobject.h"
#include "ltm.h"
#include "lzio.h"



struct lua_longjmp;  /* defined in ldo.c */


/* table of globals */
#define gt(L)             (&L->l_gt)

/* registry */
#define registry(L)       (&G(L)->l_registry)


/* extra stack space to handle TM calls and some other extras */
#define EXTRA_STACK       5


#define BASIC_CI_SIZE     8

#define BASIC_STACK_SIZE  (2*LUA_MINSTACK)



typedef struct stringtable {
  GCObject **hash;
  lu_int32 nuse;   /* number of elements */
  int size;
} stringtable;


/*
** informations about a call
*/
typedef struct CallInfo {
  StkId base;     /* base for this function */
  StkId func;     /* function index in the stack */
  StkId top;      /* top for this function */
  const Instruction *savedpc;
  int nresults;   /* expected number of results from this function */
  int tailcalls;  /* number of tail calls lost under this entry */
} CallInfo;



#define curr_func(L)  (clvalue(L->ci->func))
#define ci_func(ci)   (clvalue((ci)->func))
#define f_isLua(ci)   (!ci_func(ci)->c.isC)
#define isLua(ci)     (ttisfunction((ci)->func) && f_isLua(ci))


/*
** `global state', shared by all threads of this state
*/
typedef struct global_State {
  stringtable strt;            /* hash table for strings */
  lua_Alloc frealloc;          /* function to reallocate memory */
  void *ud;                    /* auxiliary data to `frealloc' */
  lu_byte currentwhite;        
  lu_byte gcstate;             /* state of garbage collector */
  int sweepstrgc;              /* position of sweep in `strt' */
  GCObject *rootgc;            /* list of all collectable objects */
  GCObject **sweepgc;          /* position of sweep in `rootgc' */
  GCObject *gray;              /* list of gray objects */
  GCObject *grayagain;         /* list of objects to be traversed atomically */
  GCObject *weak;              /* list of weak tables (to be cleared) */
  GCObject *tmudata;           /* last element of list of userdata to be GC */
  Mbuffer buff;                /* temporary buffer for string concatentation */
  lu_mem GCthreshold;          
  lu_mem totalbytes;           /* number of bytes currently allocated */
  lu_mem estimate;             /* an estimate of number of bytes actually in use */
  lu_mem gcdept;               /* how much GC is `behind schedule' */
  int gcpause;                 /* size of pause between successive GCs */
  int gcstepmul;               /* GC `granularity' */
  lua_CFunction panic;         /* to be called in unprotected errors */
  TValue l_registry;
  struct lua_State *mainthread;
  UpVal uvhead;                /* head of double-linked list of all open upvalues */
  struct Table *mt[NUM_TAGS];  /* metatables for basic types */
  TString *tmname[TM_N];       /* array with tag-method names */
} global_State;


/*
** `per thread' state
*/
struct lua_State {
  CommonHeader;
  lu_byte status;
  StkId top;                    /* first free slot in the stack */
  StkId base;                   /* base of current function */
  global_State *l_G;            
  CallInfo *ci;                 /* call info for current function */
  const Instruction *savedpc;   /* `savedpc' of current function */
  StkId stack_last;             /* last free slot in the stack */
  StkId stack;                  /* stack base */
  CallInfo *end_ci;             /* points after end of ci array*/
  CallInfo *base_ci;            /* array of CallInfo's */
  int stacksize;                
  int size_ci;                  /* size of array `base_ci' */
  unsigned short nCcalls;       /* number of nested C calls */
  unsigned short baseCcalls;    /* nested C calls when resuming coroutine */
  lu_byte hookmask;             
  lu_byte allowhook;            
  int basehookcount;            
  int hookcount;                
  lua_Hook hook;                
  TValue l_gt;                  /* table of globals */
  TValue env;                   /* temporary place for environments */
  GCObject *openupval;          /* list of open upvalues in this stack */
  GCObject *gclist;
  struct lua_longjmp *errorJmp; /* current error recover point */
  ptrdiff_t errfunc;            /* current error handling function (stack index) */
};


#define G(L)    (L->l_G)


/*
** Union of all collectable objects
*/
union GCObject {
  GCheader gch;
  union TString ts;
  union Udata u;
  union Closure cl;
  struct Table h;
  struct Proto p;
  struct UpVal uv;
  struct lua_State th;  /* thread */
};


/* macros to convert a GCObject into a specific value */
#define rawgco2ts(o)  check_exp((o)->gch.tt == LUA_TSTRING, &((o)->ts))
#define gco2ts(o)     (&rawgco2ts(o)->tsv)
#define rawgco2u(o)   check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))
#define gco2u(o)      (&rawgco2u(o)->uv)
#define gco2cl(o)     check_exp((o)->gch.tt == LUA_TFUNCTION, &((o)->cl))
#define gco2h(o)      check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))
#define gco2p(o)      check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))
#define gco2uv(o)     check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))
#define ngcotouv(o) \
    check_exp((o) == NULL || (o)->gch.tt == LUA_TUPVAL, &((o)->uv))
#define gco2th(o)     check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))

/* macro to convert any Lua object into a GCObject */
#define obj2gco(v)    (cast(GCObject *, (v)))


LUAI_FUNC lua_State *luaE_newthread (lua_State *L);
LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);

#endif

